class_docstr: Defines the interface for metrics.
docstr: TF summary op for this metric.
docstr_tok: ["TF","summary","op","for","this","metric","."]
code: def summary_op(self) -> tf.Operation:
      """TF summary op for this metric."""
      return self._summary_op
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import abc
  from typing import Any, Optional, Sequence, Text, Union
  from absl import logging
  import numpy
  import six
  import tensorflow
  from tf_agents.metrics import tf_metric
  from tf_agents.trajectories import trajectory
  from tf_agents.typing import types
  from tf_agents.utils import common
label_desc: Use image node_id 8 for calling the PyMetric obj's underlying member method code with example usage: obj.summary_op() and returns: self